Do all of those functions really belong inside of a journal publishing system? I would probably look rather at how to let OJS use a Customer Relationship Management system of some sort as a source of authentication and identity for the few bits of information it wants, and how to let the CRM look into OJS for any e.g. statistics it wants. That is, how can each concentrate on its mission and also serve as a component of the other? (Actually, authentication might best be provided to both from outside of either.)
More and more it seems to me that there shouldn't be *anything* at the center of an enterprise but the abstract notion of "what our business is", with useful systems clustered around that and communicating among themselves as required to realize that abstraction. Trying to make one software package do it all is just too hard. Instead, model your enterprise first and then see what products and procedures best snap in where, and what you'll need to build.
If that causes you to come up with any nifty new OJS authentication or export plugins or the like, please do consider sharing.